From: Dave Thomas <Dave@...>
Date: 2000-12-20T03:39:45+09:00
Subject: [ruby-talk:7703] Re: (Maybe) a correction for Programming Ruby

"Christoph Rippel" <crippel@primenet.com> writes:

> If I run
> 
> module A
> def A.append_features(aModule)
> p "module A was included in #{aModule} but #{aModule}.foo was not defined"
> end
> def foo
> end
> end
> 
> class  B
> include A
> end
> 
> x = B.new
> x.foo
> 
> I end up with
> >>"module A was included in B but B.foo was not defined"
> >>rr.rb:14: undefined method `foo' for #<B:0xa0398d8> (NameError)

Because you never called the _real_ append features, so the method was 
never added:

     module A
       def A.append_features(aModule)
        super                          #<<< call the real one...
        p "module A was included in #{aModule}"
       end
       def foo
       end
     end

     class  B
       include A
     end

     x = B.new
     x.foo

then foo will be defined.

Regards


Dave